Derivative Instruments - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Derivative [Line Items]
Derivative, Gain on Derivative	$ 50.9	$ 2.3
Derivative, Fair Value, Net	48.0	12.8
Northwest Natural Gas Company [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	51.8	14.1
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	$ 3.8	$ 1.3
Northwest Natural Gas Company [Member] \| Gas Year 2020 - 2021 \| Financial [Member]
Derivative [Line Items]
TargetHedgeAchieved	53.00%
Northwest Natural Gas Company [Member] \| Gas Year 2020 - 2021 \| Physical [Member]
Derivative [Line Items]
TargetHedgeAchieved	17.00%
Northwest Natural Gas Company [Member] \| Gas Year 2021 - 2022 \| Financial [Member]
Derivative [Line Items]
TargetHedgeAchieved	60.00%
Northwest Natural Gas Company [Member] \| Gas Year 2021 - 2022 \| Physical [Member]
Derivative [Line Items]
TargetHedgeAchieved	19.00%

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Fair value, after offset of derivative liability, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, before offset against an obligation to return collateral under a master netting arrangement. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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- Definition

Fair value, after offset of derivative asset, of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, elected not to be and before offset against a right to receive collateral under a master netting arrangement. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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- Definition

Fair value of the assets less the liabilities of a derivative or group of derivatives.

+ References

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Amount of increase in the fair value of derivatives recognized in the income statement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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